In the field of marine seismic surveying, seismic data acquisition entails deploying ocean bottom cables (“OBCs”) containing paired combinations of hydrophone/geophone sensors (i.e., receivers) at or near the ocean bottom. Seismic pressure sources near the ocean surface are then activated and the seismic signals received by each of the component phones in the hydrophone/geophone combination sensors (i.e., pressure for the hydrophone sensors and particle velocity for the geophone sensors) are recorded.
Typically, the signals received by each of the component phones are combined numerically in various ways to preferentially enhance that part of the signal due to reflected energy arriving from below the sensors and suppress that part of the signal due to reflected energy arriving from above the sensors. The reflected energy arriving from below the sensors indicate the depth and location of the reflecting geological features. The data from the received seismic signals may then be interpreted to aid in determining the presence of hydrocarbon reserves. The undesirable reflected energy arriving from above the sensors is known as a “ghost” reflection. A ghost reflection occurs when seismic energy initially reverberates upward from the shallow subsurface (i.e., the earth below the ocean bottom) and then is reflected back downward from the ocean surface. Ghost reflections are represented as noise in the “true” reflected signal (i.e., the reflected energy arriving from below the sensors) and may mask (or hide) useful information regarding the location or attributes of geological features.
Presently, various processes (i.e., “deghosting” processes) are known for suppressing ghost reflections in seismic data received from OBCs. These processes comprise a “black box” solution in which an algorithm is utilized to compute a deghosting component of an arithmetic operation for eliminating the effects of ghost reflections in seismic data. A significant drawback in current deghosting processes is that hydrophone/geophone receivers are treated as an independent entity with no predictable correlation with other sensors in the vicinity. As a result, in many cases the deghosting components are erroneously computed as being highly variable between receiver locations within a survey.
It is with respect to these considerations and others that the various embodiments of the present invention have been made.